On the sources and sinks of atmospheric VOCs: an integrated analysis of recent aircraft campaigns over North America.
Xin Chen, Dylan B Millet, Hanwant B Singh, Armin Wisthaler, Eric C Apel, Elliot L Atlas, Donald R Blake, Ilann Bourgeois, Steven S Brown, John D Crounse, Joost A de Gouw, Frank M Flocke, Alan Fried, Brian G Heikes, Rebecca S Hornbrook, Tomas Mikoviny, Kyung-Eun Min, Markus Müller, J Andrew Neuman, Daniel W O'Sullivan, Jeff Peischl, Gabriele G Pfister, Dirk Richter, James M Roberts, Thomas B Ryerson, Stephen R Shertz, Chelsea R Thompson, Victoria Treadaway, Patrick R Veres, James Walega, Carsten Warneke, Rebecca A Washenfelder, Petter Weibring, Bin Yuan
Author Information
Xin Chen: Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA.
Dylan B Millet: Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA.
Hanwant B Singh: NASA Ames Research Center, Moffett Field, CA, USA.
Armin Wisthaler: Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria.
Eric C Apel: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA.
Elliot L Atlas: Department of Atmospheric Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.
Donald R Blake: Department of Chemistry, University of California, Irvine, Irvine, CA, USA.
Ilann Bourgeois: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Steven S Brown: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
John D Crounse: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
Joost A de Gouw: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Frank M Flocke: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA.
Alan Fried: Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA.
Brian G Heikes: Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA.
Rebecca S Hornbrook: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA.
Tomas Mikoviny: Department of Chemistry, University of Oslo, Oslo, Norway.
Kyung-Eun Min: School of Earth Science and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea.
Markus Müller: Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria.
J Andrew Neuman: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Daniel W O'Sullivan: United States Naval Academy, Chemistry Department, Annapolis, MD, USA.
Jeff Peischl: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Gabriele G Pfister: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA.
Dirk Richter: Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA.
James M Roberts: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Thomas B Ryerson: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Stephen R Shertz: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA.
Chelsea R Thompson: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Victoria Treadaway: Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA.
Patrick R Veres: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
James Walega: Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA.
Carsten Warneke: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Rebecca A Washenfelder: Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
Petter Weibring: Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA.
Bin Yuan: Institute for Environmental and Climate Research, Jinan University, Guangzhou, China.
We apply a high-resolution chemical transport model (GEOS-Chem CTM) with updated treatment of volatile organic compounds (VOCs) and a comprehensive suite of airborne datasets over North America to (i) characterize the VOC budget and (ii) test the ability of current models to capture the distribution and reactivity of atmospheric VOCs over this region. Biogenic emissions dominate the North American VOC budget in the model, accounting for 70 % and 95 % of annually emitted VOCcarbon and reactivity, respectively. Based on current inventories anthropogenic emissions have declined to the point where biogenic emissions are the dominant summertime source of VOC reactivity even in most major North American cities. Methane oxidation is a 2x larger source of nonmethane VOCs (via production of formaldehyde and methyl hydroperoxide) over North America in the model than are anthropogenic emissions. However, anthropogenic VOCs account for over half of the ambient VOC loading over the majority of the region owing to their longer aggregate lifetime. Fires can be a significant VOC source episodically but are small on average. In the planetary boundary layer (PBL), the model exhibits skill in capturing observed variability in total VOC abundance ( = 0:36) and reactivity ( = 0:54). The same is not true in the free troposphere (FT), where skill is low and there is a persistent low model bias (~ 60 %), with most (27 of 34) model VOCs underestimated by more than a factor of 2. A comparison of PBL: FT concentration ratios over the southeastern US points to a misrepresentation of PBL ventilation as a contributor to these model FT biases. We also find that a relatively small number of VOCs (acetone, methanol, ethane, acetaldehyde, formaldehyde, isoprene C oxidation products, methyl hydroperoxide) drive a large fraction of total ambient VOC reactivity and associated model biases; research to improve understanding of their budgets is thus warranted. A source tracer analysis suggests a current overestimate of biogenic sources for hydroxyacetone, methyl ethyl ketone and glyoxal, an underestimate of biogenic formic acid sources, and an underestimate of peroxyacetic acid production across biogenic and anthropogenic precursors. Future work to improve model representations of vertical transport and to address the VOC biases discussed are needed to advance predictions of ozone and SOA formation.
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